Segmented tire mold having hinged arcuate tread sectors

ABSTRACT

A three-piece segmented tire mold including opposed sidewall mold sections that are movable toward and away from each other for molding the sidewall portions of a pneumatic tire, and further including a series of arcuate tread mold sectors adapted to register with the opposed sidewall mold sections and with the arcuate tread sectors being hinged to one of said mold sections so as to be movable around a fixed hinge point for the purpose of receiving a tire and subsequently permitting removal of the same following vulcanization.

United States Patent Hottle [54] SEGMENT'ED TIRE MOLD HAVING HINGEDARCUATE TREAD SECTORS [72] Inventor: Dwight E. Hottle, 2866 LakelandParkway, Cuyahoga Falls, Ohio 44224 [22] Filed: Oct. 19,1970

[21] Appl. No.: 81,688

[52] US. Cl ..425/46, 425/45 [51] Int. Cl. ..B29h 5/02 [58]FieldofSearch ..18/17 K, 17 W, 17 T, 42T,

[56] References Cited UNITED STATES PATENTS 1,179,898- 4/1916Coffeyetal. ..18/17KUX 3,460,197 8/1969 Cantarutti et a1. .....1s/17 K x3,171,163 3/1965 Ford etal ..25/121 x 3,097,397 7/1963 Leach et a1...249/171 1451 Nov. 28, 1972 FOREIGN PATENTS OR APPLICATIONS 771,55311/1967 Canada ..18/17K 4/l964 Germany ..18/17W Primary ExaminerJ.Howard Flint, Jr. AttorneyFreeman & Taylor [57], ABSTRACT 2 Claims, 9Drawing Figures PLTENTEDnnv 2a 1912 SHEET 1 OF 5 FIG./

INVENTOR. DWIGHT E. HOTTLE JMMMV 4744,

ATTORNEYS PATENTEDNHV28 m2 3.704.082

SHEET 2 UF 5 isms? 22 22 DWIGHT E. HOTTL.E

FIG. 5

A T TORNEYS PATENTEU 2 8 I97? I 3. 7 04,0 8 2 sum 3 0F 5 FIG. 3

INVENTOR. DWIGHT E. HOTTLE ATTORNEYS SEGMENTED TIRE MOLD HAVING HINGEDARCUATE TREAD SECTORS BACKGROUND OF THE INVENTION halves meet at thelongitudinal or center line of the tire so as to form a flash point inthe mid-portion of the tread region of the tire.

While tire molds of this type have long been known, the same have beenfound to possess certain disadvantages.

First, the presence of flash in tire. molding operations of this type isvery difficult, if not impossible, to avoid and as a result in the useof two-part molds, this flash occurs in the mid-section of the treadregion which is highly disadvantageous from an appearance andperformance standpoint.

Second, with the advent of radial ply belted tires includinghigh-strength cord members, it has been found difficult to remove suchtires from the mold due to the inability of the same to be broken awayfrom the mold especially in the tread region thereof.

It was for the foregoing reasons that segmented tire molds, featuringthree-mold sections, were introduced to the art. In segmented molds ofthe three-part type, normally one mold section is employed to provideone side wall surface of the tire, another mold is used to provide theopposed sidewall surface of the tire, and an expandable, articulatedtread mold sector is employed to provide the tread section of the tire.By virtue of the expandable nature of this type of mold, removal of thetires from the mold is greatly facilitated.

DESCRIPTION OF THE PRIOR ART Prior art patents illustrating segmentedmold constructions of the type above-discussed are believed to berepresented in the following U.S. Pat. NOS.

Doughty U.S. Pat. No. 1,101,732 Finlayson U.S. Pat. No. 1,132,250Doughty U.S. Pat. No. 1,260,990 Shrum et al. U.S. Pat. No. 1,475,032Balle U.S. Pat. No. 3,082,480 Pacciarini et al. U.S. Pat. No. 3.337.918Balle et al. U.S. Pat. No. 3,396,221 Cantarutti et al. U.S. Pat. No.3,460.197 Turk et al. U.S. Pat. No. 3,461,502

SUMMARY OF THE INVENTION The present invention envisions hinging thetread mold sectors adjacent one axial edge thereof to one of thesidewall mold sections. By this arrangement a fixed pivot point isprovided and by use of a piston, for example, secured adjacent to theremaining axial edge of each sector, the arcuate tread mold sectors canbe pivoted into and out of molding position.

The present invention, utilizing structure of the type above-described,provides at least three distinct advantages over the known prior art.

because of the fact that these will be self-aligning, with v the resultthat lesser machine tolerances may be required.

.As a third advantage it will be noted that by virtue of this pivotingconstruction and the extension of the tread mold sectors down into thecrown region of the tire, that when molding is completed and it isdesired to remove the tire that then, in that event, the crown moldingportion will serve in effect as a pry bar to separate the cured tirefrom the remaining portions of the mold.

Production of an improved segmented tire mold having the above-describedfeatures accordingly becomes the principal object of this invention,with other objects thereof becoming more apparent upon a reading thefollowing brief specification considered and interpreted in view of theaccompanying drawings.

OF THE DRAWINGS FIG. 1 is a perspective view illustrating the improvedsegmented mold in closed position, with the top mold section beingseparated therefrom.

FIG. 2 is a similar perspective view but being partly broken away insection and showing the tread mold sectors in their open position.

FIGS. 3 and 4 are plan views respectively illustrating the segmentedmold in closed and open positions.

FIG. 5 is a partial sectional view illustrating a green uncured tirereceived within the segmented mold in open position prior to moldclosure and cure.

FIG. 6 is a similar sectional view to FIG. 5 showing the position of thecomponent parts in closed or curing position.

FIG. 7 is a similar sectional view showing the position of the componentparts after molding has been completed and the segmented mold has beenmoved to open position.

FIGS. 8 and 9 are similar sectional views showing the I DESCRIPTION OFTHE PREFERRED EMBODIMENT Referring now to the drawings and in particularto FIG. 1 thereof, the improved segmented mold, generally designated bythe numeral 10, includes an upper mold section 11, a lower mold section12, and an articulated tread mold 13, with the tread mold section 13being made up of individual tread mold sectors 14,14 that are hingedbetween open and closed position by virtue of pistons 15,15, as clearlyshown in FIGS. 1 and 2 of the drawings.

In this regard, such pivotal movement by the piston 15,15 is effectuatedaround fixed pivot points 16,16 that serve as a point of connectionbetween a series of lugs 17,17 carried by the lower mold section 12, anda surface 121;, and a recess 12c, within which the conventional beadring 20 may be received, with bead ring 20 being securedin place by useof one or-more bolts 21,21 and with the entire. mold section 12 beingsecured to a lower platen LP by virtue of 22,22 as clearly shown in thedrawings. Extending radially outward from the peripheral edge also ineludes'a projecting lug having an opening I pivotally mounted toappropriate mounting pad 29 that of the lower mold section 12 are aseries of yoke-like lugs 17,17 having opposed bores 17d,17a within whicha pin 16b maybe received. I

Turning now to FIG. 6 of the. drawings for a con.-

sideration of the structural characteristics of the upper mold section11, it will be noted that the same is similarly contouredsojasto'provide a design-imparting surface '1 1a for molding thesidewall of the tire, while a registry surfacelZb and a recess 12c aresimilarly provided for the purpose-of registering with the arcuate treadmold sectors 14,14 and receiving an upper bead ring 23, with bead ring23 being secured in position as showninFlG. 6rby the use of screws24,24. Again, tapped openings 25,25 are provided for the purpose ofattaching the upper mold section to the upper platen (not shown) of thevulcanizing press. With reference to the 'press construction, it isbelieved that this is well known in the art, but in the drawings thereis illustrated a construction wherein a bladder B is positioned betweenthe upper and lower mold sections 1 l and 12 and held by rings 30 and40.

Referring now to FIGS. 1 and 2 for a description of the tread moldsection 13, it will be noted that preferably each arcuate tread sector14 is of identical configuration so as to include an upper axial edge14a and a lower axial edge 14b, with these edge surfaces 14a and 14bbeing connected on the interior portion of the mold by an innerdesign-imparting surface 140 and on the outer side by an outerperipheral wall 14d. Further, the arcuate ends of the individual treadsectors 14,14 are defined by end walls l4e,14e as best shown in FIG. 2of the drawings.

With reference to the upper edge 14a, it will be noted that this iscontoured for registering reception within the recess 11b of the uppermold section 11, while the lower edge surface 14b is similarly contouredfor reception within the surface 12b of the lower mold surface 12. Whenthe component parts are positioned in the closed position of FIG. 6, itwill be noted that the inner molding surfaces 11a, 14c, and 12a incontiguous registry with each other so as to provide an enclosed chamberwithin which final curing of a pneumatic tire can be achieved.

In addition to the aforementioned component parts, each mold sector 14includes, adjacent the arcuate ends 14e,14e and the lower edge 14b, apair of lug members 18,18 that are provided with an appropriate openingtherein for reception of the pin 16b, as clearly shown in the drawings.Lug members 18,18 are received between the legs of yoke-like lugs 17,17and held there by pins 1612,1612. Additionally, for the purposes ofeffectuating pivoting around this defined hinge point 16, the upperportion of the peripheral wall 14d is secured to the lower platen LP ina conventional arrangernent.

In use or operation of the improved segmented mold 10, it will first beassumedthat the component parts have been assembled to the conditionshown and, further, that the pistons 15,15'have been actuated and arms15a,15a have been retracted so as to move thearcuate tread sectors 14,14to the position of FIG. 5.

At this time a green uncured tire GT may be positioned overtheuninflated bladder B, and will be noted that the green tire-is resting(see FIG. 5) on one or more of the design-imparting ribs 14f,- 14f, withthe green tire also being in close adjacency with the crown moldingportion 143. By this arrangemermthe longitudinal center line 50 of thetire will be pre-positioned by the cradling effect just describedso asto be in alignment with true horizontal. Thus, when the longitudinalcenter line of the arcuate sectors is moved into the closed position,these center lines 50 and 60 will be in alignment so that an accuratelymolded tire will result.

Assuming positioning as just described, the pistons 15,15 will then beactuated in unison to move the arcuate sectors 14,14 around the hingepoint 16 and into the closed position of FIG. 6.

At this time the bladder B can be inflated to expand into the green tireGT with the design-imparting surfaces that are defined by the bead rings20 and 23, the upper mold surface 112., the arcuate tread moldingsurfaces l4c,l4c, the lower mold surface 12a, and the lower bead ring20. When curing has been completed, the first operation will be tocollapse and withdraw the bladder to the position'shown in FIG. 7, andfollowing this, the upper platen and the upper mold section 1 1 attachedthereto will be moved away from the remaining components so as to beseparated from the tire.

At this time the pistons 15,15 can be operated again in unison in thereverse direction to hinge or move the arcuate sectors 14,14 aroundtheir common hinge points 16,16 to the position of FIG. 7. During thisarrangement it will be noted that the crown mold portions 143,143 ofeach sector 14 will engage the crown of the cured tire and will, ineffect, cause it to separate from the lower molding surface 12a, asshown in FIG. 7.

At this time manual removal or automatic removal of the tire is readilyachieved since the tire has been separated from all mold surfaces and ismerely resting on the crown portions 14g,14g as shown in FIG. 7 of thedrawings. Furthermore, the tread mold sectors 14,14 will have beenpulled out of the way so that the crown mold portions 14h,14h on the topof sectors 14,14 will notinterfere with tire removal.

In the modified from of the invention shown in FIGS. 8 and 9, similartype of operation is envisioned except for the fact that a differentmeans of effectuating pivoting is utilized.

Accordingly, in FIGS. 8 and 9 each of the pistons 15,15 of FIGS. 1through 7 are replaced by an actuating piston 80 is secured to theunderside of the lower platen LP and having a roller mechanism 81 onpiston arm 83 that is designed to engage the surface 14b of tread moldsector 14, with the piston 80 being secured to the lower platen byappropriate bolts 82,82 and with the piston arm 83 being extendable fromthe position of FIG. 8 to the position of FIG. 9 in known fashion.

Accordingly, and as shown in FIGS. 8 and 9, upon actuating of thepistons 80,80 to the extended position, the mold sectors 14,14 willagain move around pivot point 16 to the open position with a similarresult as previously described. Retraction of piston arms 83,83 willlikewise permit the sectors to close, as shown in FIG. 8.

It accordingly follows that operation of the device is as previouslydescribed, with the exception that a different type of pistonarrangement is utilized in this modification of the invention.

While a full and complete description of the invention has been setforth in accordance with the dictates of the Patent Statutes, it is tobe understood that the device is not intended to be limited to thespecific form or forms shown herein.

Accordingly, modifications of the invention may be resorted to withoutdeparting from the spirit hereof or the scope of the appended claims.

What is claimed is:

l. A segmented tire mold of the character described, comprising;

A. a lower mold section having a sidewall molding surface thereon;

B. a plurality of arcuate tread mold sectors 1 having tread moldingsurfaces and 2. each being hinged to said lower mold section around atleast one fixed pivot point a. whereby said tread mold sectors may movebetween a closed position wherein the tread mold surfaces thereof are incontiguous registry with the sidewall molding surfaces, and an openposition wherein the ends of said tread mold sections are spaced fromeach other and said sidewall molding surfaces of said first moldsection;

C. means for pivoting said tread mold sectors around said pivot pointbetween said open and closed positions and moving said sectors bothradially and axially with respect to said first mold section, said meansbeing a piston interconnecting the lower mold section with an upperportion of each said tread mold section whereby a lifting movement isperformed by said tread molding sections during movement from saidclosed position to said open position; and

D. a second mold section having a sidewall molding surface complementalto said first sidewall mold surface and adapted to be in registrytherewith when said tread mold sectors are in said closed position,whereby the molding surfaces of said first mold section, said secondmold section, and said arcuate tread sections form a tire molding cavitywhen in registry with each other.

2. The device of claim 1 further characterized by the fact that each ofsaid tread mold sectors include a radially inwardly pro ecting surfacedefining the crown region of said tire; said inwardly projecting surfaceof said mold sector acting as a pry bar around said hinge point duringremoval of said tire following vulcanization thereof upon radial andaxial movement of said tread mold sectors.

1. A segmented tire mold of the character described, comprising; A. alower mold section having a sidewall molding surface thereon; B. aplurality of arcuate tread mold sectors
 1. having tread molding surfacesand
 2. each being hinged to said lower mold section around at least onefixed pivot point a. whereby said tread mold sectors may move between a''''closed'''' position wherein the tread mold surfaces thereof are incontiguous registry with the sidewall molding surfaces, and an''''open'''' position wherein the ends of said tread mold sections arespaced from each other and said sidewall molding surfaces of said firstmold section; C. means for pivoting said tread mold sectors around saidpivot point between said ''''open'''' and ''''closed'''' positions andmoving said sectors both radially and axially with respect to said firstmold section, said means being a piston interconnecting the lower moldsection with an upper portion of each said tread mold section whereby alifting movement is performed by said tread molding sections duringmovement from said ''''closed'''' position to said ''''open''''position; and D. a second mold section having a sidewall molding surfacecomplemental to said first sidewall mold surface and adapted to be inregistry therewith when said tread mold sectors are in said closedposition, whereby the molding surfaces of said first mold section, saidsecond mold section, and said arcuate tread sections form a tire moldingcavity when in registry with each other.
 2. The device of claim 1further characterized by the fact that each of said tread mold sectorsinclude a radially inwardly projecting surface defining the crown regionof said tire; said inwardly projecting surface of said mold sectoracting as a pry bar around said hinge point during removal of said tirefollowing vulcanization thereof upon radial and axial movement of saidtread mold sectors.
 2. each being hinged to said lower mold sectionaround at least one fixed pivot point a. whereby said tread mold sectorsmay move between a ''''closed'''' position wherein the tread moldsurfaces thereof are in contiguous registry with the sidewall moldingsurfaces, and an ''''open'''' position wherein the ends of said treadmold sections are spaced from each other and said sidewall moldingsurfaces of said first mold section; C. means for pivoting said treadmold sectors around said pivot point between said ''''open'''' and''''closed'''' positions and moving said sectors both radially andaxially with respect to said first mold section, said means being apiston interconnecting the lower mold section with an upper portion ofeach said tread mold section whereby a lifting movement is performed bysaid tread molding sections during movement from said ''''closed''''position to said ''''open'''' position; and D. a second mold sectionhaving a sidewall molding surface complemental to said first sidewallmold surface and adapted to be in registry therewith when said treadmold sectors are in said closed position, whereby the molding surfacesof said first mold section, said second mold section, and said arcuatetread sections form a tire molding cavity when in registry with eachother.